Power brushing and chemical denture cleansers induced color changes of pre-polymerized CAD/CAM denture acrylic resins

Denture wearers are advised to follow the protocol of using both mechanical and chemical hygiene methods. In this study, the in-vitro color stability of heat-cured, light-cured and newly developed pre-polymerized CAD/CAM acrylic resin base materials were evaluated after exposure to mechanical brushing and chemical denture cleansers. Two polymethyl methacrylate (PMMA) (heat-cured, and pre-polymerised CAD/CAM) and one urethane dimethacrylate based resin denture base material were subjected to mechanical brushing, followed by immersion in chemical denture cleansers (Corega, 5.25% Sodium hypochlorite (NaOCl), and 0.2% chlorhexidine gluconate (CHG)) and thermal-cycling to simulate one-year of normal prosthesis use. Baseline and final color measurements were determined and the difference in color was calculated using bench-top UV light visible spectrophotometer. The highest (29.69 +/- 1.84) and lowest (19.03 +/- 8.78) mean Delta E was observed with light-cured and CAD/CAM materials immersed in 0.2% CHG, respectively. Tukey's post-hoc test showed that heat cured and light-cured resins immersed in either of the denture cleansers showed no significant differences (p > 0.05) in the mean Delta E values. On the contrary, CAD/CAM materials immersed in either of the denture cleansers demonstrated significant differences in the mean Delta E values (p